1. Field of the Invention
This invention relates to the field of computers, and in particular to the field of display devices.
2. Description of Related Art
Conventional presentation and display techniques are becoming increasingly less effective and efficient as the quantity of available information continues to increase. Hypertext and hyperlinks provide a dramatic increase in the ease of locating and viewing related information items compared to pre-hypertext methods, but are limited by their singularity. While reading a document that contains multiple hypertext items, the reader may access each item directly, but is not provided a view of how these individual items relate to each other, or whether there are other items more closely related to the document being read that also relate to these same hypertext items.
Methods for identifying relations among information items are becoming increasingly common. Entire libraries of books can be categorized and cross referenced. The laws and court cases and opinions of an entire country have been categorized and cross referenced. Starting at virtually any point in each system, a user can navigate within the system along a particular path of inquiry using identified relations between information items. For example, a person may be viewing a book on astronomy, which contains a reference to Copernicus. Following a link to a text on Copernicus, the person may find a link to Galileo, then to Newton, or Michelangelo, and so on. Although these links are well defined, and within the reference system form a web-like or lattice interconnection network, the user""s navigation abilities through this complex network are limited to single step links, with do map to provide an overall picture of where in the general scheme of things each single step may lead, where alternative steps may be taken, or what interesting steps may be missed.
Tools such as tables of content and indexes are employed for locating related items in a text, and attempts have been made to apply these tools to larger search tasks. Items are classified by categories within a hierarchical structure, and the user is provided a means for locating items based on the hierarchy, much like the organization of a book by chapters, sections, sub-sections, etc. The above library example references to Copernicus and Galileo would likely be categorized at the same level in a hierarchy of xe2x80x9cphysical science: astronomy: early historyxe2x80x9d. Other astronomers prominent in the early history of astronomy would also be located at this level in the hierarchy. Conventional information indexes present the hierarchical information as a tree structure, from which the user can determine what information is available and how the individual items are related. Such a hierarchical organization structure is also common for organizing files in a computer system. Related items are placed in a folder, related folders are placed in a higher level folder, groups of related higher level folders are placed on a node in a network, and so on. Tools are provided for traversing the hierarchy by opening each subsequent node to reveal subsequent lower level nodes. Provided that sufficient display space is available, the user can display the contents of each of the opened nodes to place the current node xe2x80x9cin contextxe2x80x9d with the overall structure.
Hierarchical display techniques, however, are limited to the display of information arranged in a hierarchical fashion, and limited to the topic used to form the hierarchy. In the library example, Newton may be related to other information items that have no bearing on the early history of astronomy, and these other items would not be included in the above example xe2x80x9cphysical science: astronomyxe2x80x9d hierarchy. In like manner, Michelangelo""s contribution to astronomy might not warrant his inclusion in the xe2x80x9cphysical science: astronomyxe2x80x9d hierarchy, although a relationship to Galileo and Newton may exist, for example when viewed from a church history viewpoint. Typically, a hierarchical display technique relies on the use of hypertext and hyperlinks to provide such secondary links to other items, outside the task of displaying the hierarchy.
Rarely, if ever, are information items related solely by a hierarchical relationship. Most information items are related to each other in a variety of ways, at various degrees of separation. A graphic representation of the various relationships typically forms a web-like or lattice structure. The conventional display of items that are related in a lattice structure is typically effected by presenting the items in a two dimensional form, with arrows indicating each link, as illustrated in FIG. 1.
FIG. 1 illustrates ten information items, or nodes, I0-I9, interconnected by seventeen different links, identified by Lmn, where m and n are the numerical references (0-9) to the interconnected nodes I0-I9. The links Lmn are illustrated as bidirectional links, although unidirectional relationships and links may exist in some applications of a lattice structure. By following the links, a user can determine relationships between these information items, and navigate via the links or directly to a node of interest.
The illustration of FIG. 1 has a number of limitations. The representation of ten nodes and their seventeen relationships forms a fairly complex image; the representation of hundreds of nodes and thousands of relationships in this manner would be virtually unusable as a navigation aide beyond, perhaps, a single link traversal. The representation of FIG. 1 would not be feasible for potentially thousands of nodes and millions of relationships, or more. The other limitation to the conventional lattice display of FIG. 1 is its uniformity. As compared to a hierarchical presentation, wherein the location of a node indicates its relevance within the general scheme of things, it is difficult to associate an implied significance to a node based on its appearance in the conventional lattice display. In general, this may not present a problem, because the significance of each node in a lattice structure is usually indeterminable, without an assumed context. That is, for example, the nodes corresponding to Galileo, Newton, Copernicus, and Michelangelo in the above library example are of equal significance from the context-free viewpoint of the library. Another limitation of the conventional lattice display is that the organization of the display does not convey an immediate impression of the relationships among the items. For example, it is not immediately apparent that node I6 is closely related to nodes I5 and I2, but only distantly related to node I9, except by tracing each of the arrows from the node I6, and then from each of the immediately connected nodes to subsequent nodes. Some conventional lattice displays attempt to overcome this limitation by highlighting all the nodes that are connected to a selected node, but this solution is again limited to single link relationships and a single step navigation approach.
It is an object of this invention to provide a method and device for presenting related information items in a manner that facilitates a recognition of the relationship among the information items. It is a further object of this invention to provide a method and device for presenting related information items that facilitates a recognition of relationships based upon a context. It is a further object of this invention to provide a method and device for presenting information based on the degree of separation between and among related items. It is a further object of this invention to provide a method and device for presenting information that is suitable for the display of a large number of related items.
These objects and others are achieved by dynamically organizing and displaying related information items in dependence upon a user""s indicated point of reference. The user""s point of reference is displayed prominently, and information items that are related to the point of reference are displayed with a prominence that reflects each item""s degree of separation from the user""s point of reference. Both size and position are used to indicate prominence. To present a consistent interface regardless of the user""s point of reference, recursive techniques, such as fractal based algorithms, are used in a preferred embodiment.